I've been able to build things that I otherwise would not have been able to build, in the free time that I have:

- a VST audio plugin

- a wedding website with RSVP functionality

- a relaxing game for my wife

At work, I've been able to build much more than I would have been capable of in the past. I'm a backend eng, and it allows me to build much much nicer frontends than I've ever been able to do in the past.

And before you tell me that the code is crap - it doesn't matter! It may or may not be good code, but it works and serves it's purpose very well. Anyways, I'm I'm not launching a rocket, or putting software into cars.